Flint fire starters are often carried as a backup method of starting a fire when traveling outdoors in the event a primary means of starting a fire is lost, breaks, or becomes unusable. Methods that require one hand for operation are especially useful as they can still be used in case of an injury to a hand or arm. Flint fire starters of this style are typically very basic and use an ignition method commonly used in lighters, where a spring presses a flint against a friction wheel, which causes a spark when the wheel is rotated. Because these devices are very simple, they do not allow for storage that might hold tinder or replacement flints.
It is also common for fire starters to have a construction that includes a main body with a slot through the top for the friction wheel to sit. A pin then passes through both sides of the slot and through the flint wheel so that the friction wheel is supported on both sides and can freely rotate. This allows for easy and secure attachment but can make it hard to get the spark as close to the tinder as possible.